Constriction of the trabecular smooth muscle and helicine arteries induced by sympathetic innervation makes the penis flaccid, with blood pressure in the cavernosal sinuses of the penis near venous pressure. Acetylcholine is thought to decrease sympathetic tone. This may be important in a permissive sense for adequate trabecular smooth muscle relaxation and consequent effective action of other mediators in achieving sufficient inflow of blood into the lacunar spaces. When the trabecular smooth muscle relaxes and helicine arteries dilate in response to parasympathetic stimulation and decreased sympathetic tone, increased blood flow fills the cavernous spaces, increasing the pressure within these spaces so that the penis becomes erect. As the venules are compressed against the tunica albuginea, penile pressure approaches arterial pressure, causing rigidity. Once this state is achieved, arterial inflow is reduced to a level that matches venous outflow.
Prevention of some of the causes that contribute to the development of erectile dysfunction can decrease the chances of developing the problem. For example, if a person decreases their chances of developing diabetes, heart disease, and hypertension, they will decrease their chances of developing erectile dysfunction. Other things like stopping smoking, eating a healthy diet (heart healthy with adequate vitamin intake), and exercising daily may reduce a person's risk.
Treatments include psychotherapy, adopting a healthy lifestyle, oral phosphodiesterase type V (PDE5) inhibitors (Viagra, Levitra, Cialis, Stendra, and Staxyn), intraurethral prostaglandin E1 (MUSE), intracavernosal injections (prostaglandin E1 [Caverject, Edex], Bimix and Trimix), vacuum devices, penile prosthesis and vascular surgery, and (in some cases) changes in medications when appropriate.
This inflatable penile prosthesis has 3 major components. The 2 cylinders are placed within the corpora cavernosa, a reservoir is placed beneath the rectus muscle, and the pump is placed in the scrotum. When the pump is squeezed, fluid from the reservoir is transferred into the 2 cylinders, producing a firm erection. The deflation mechanism is also located on the pump and differs by manufacturer.
A rigid or nearly rigid erectile response to intracavernous injection of pharmacologic test doses of a vasodilating agent (see below) indicates adequate arterial and veno-occlusive function. This suggests that the patient may be a suitable candidate for a trial of penile injection therapy. Genital stimulation may be of use in increasing the erectile response in this setting. This diagnostic technique also may be used to differentiate a vascular from a primarily neuropathic or psychogenic etiology. Patients who have an inadequate response to intracavernous pharmacologic injection may be candidates for further vascular testing. It should be recognized, however, that failure to respond adequately may not indicate vascular insufficiency but can be caused by patient anxiety or discomfort. The number of patients who may benefit from more extensive vascular testing is small, but includes young men with a history of significant perineal or pelvic trauma, who may have anatomic arterial blockage (either alone or with neurologic deficit) to account for erectile dysfunction.
Among the phenomena in the ageing man are a decrease in erectile function and testosterone levels. Add to these, increased risk for CVD, muscle wasting, decrease in bone density and libido, with all of these factors having an interplay with testosterone metabolism.33 Androgens play a key role in maintaining erectile function through four main mechanisms. Androgen deprivation has been shown to result in impairment of NO synthase release, altered PDE5 expression and activity, impaired cavernosal nerve function, and contribution to veno-occlusive disease in the penis.34 The role of testosterone replacement therapy (TRT) as a potential to improve erectile function in the man with ED remains an issue for patient and physicians who are comfortable treating androgen deficiency which include primary care physicians and specialists. Androgens are known to have a significant impact on the function of the smooth musculature within the corpus spongiosum.35

Because of the difficulty in defining the clinical entity of erectile dysfunction, there have been a variety of entry criteria for patients in therapeutic trials. Similarly, the ability to assess efficacy of therapeutic interventions is impaired by the lack of clear and quantifiable criteria of erectile dysfunction. General considerations for treatment follow:
The Latin term impotentia coeundi describes simple inability to insert the penis into the vagina; it is now mostly replaced by more precise terms, such as erectile dysfunction (ED). The study of erectile dysfunction within medicine is covered by andrology, a sub-field within urology. Research indicates that erectile dysfunction is common, and it is suggested that approximately 40% of males with erectile dysfunction or impotence, at least occasionally.[35] The condition is also on occasion called phallic impotence.[36] Its antonym or opposite condition is priapism.[37][38]
Following a detailed discussion about the history of erectile dysfunction and its risk factors, your doctor will examine the testicles and penis to help determine the cause of erectile dysfunction. Your doctor will check reflexes and pulses in the area to see if problems with blood vessels or nerves are contributing to the erectile dysfunction. If necessary, your doctor will order tests to help diagnose erectile dysfunction.
Traditionally, erectile impotence (the classical definition of impotence) is the failure to achieve penile erection during intercourse. It may have either physical or psychological causes. Alcoholism, endocrine disease, and neurological disorders are typical physical causes. Psychological causes include anxiety over performance, hostility or other negative feelings toward the sexual partner, and stress, anxiety, depression, or other emotional conflicts outside of the relationship. Erectile impotence occasionally occurs with age and, although attributed by the individual to the aging process itself, it is usually secondary to disorders of aging, such as faulty blood circulation or prostate disease. In cases of impotence caused by blood vessel dysfunction, an insufficient supply of blood flows into the penis, or the blood diffuses out into adjacent tissues.
CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is sage, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.
The lab testing obtained for the evaluation of erectile dysfunction may vary with the information obtained on the health history, physical examination, and recent lab testing. A testosterone level is not necessary in all men; however, a physician will order labs to determine a patient's testosterone level if other signs and symptoms of hypogonadism (low testosterone) such as decreased libido, loss of body hair, muscle loss, breast enlargement, osteoporosis, infertility, and decreased penile/testicular size are present.

However, men are affected psychologically when it comes to achieving erections. For instance, if a man is with a woman for the first time, or even before he feels comfortable with her, he may suffer from performance anxiety. In such a situation, his mind and body are both saying yes, but then they become out of sync. The body is then saying yes, but the mind is filled with question. “Will I be able to perform?” “How long will I last?” “Am I big enough to satisfy her?” “Is she looking at that mole on my stomach?” All kinds of questions may be going through a man’s mind upon getting in bed, and these can be distracting, they can lead to self-doubt, and therefore, failure to achieve or maintain an erection.


The National Institutes of Health Consensus Development Conference on Impotence was convened to address (1) the prevalence and clinical, psychological, and social impact of erectile dysfunction; (2) the risk factors for erectile dysfunction and how they might be used in preventing its development; (3) the need for and appropriate diagnostic assessment and evaluation of patients with erectile dysfunction; (4) the efficacies and risks of behavioral, pharmacological, surgical, and other treatments for erectile dysfunction; (5) strategies for improving public and professional awareness and knowledge of erectile dysfunction; and (6) future directions for research in prevention, diagnosis, and management of erectile dysfunction. Following 2 days of presentations by experts and discussion by the audience, a consensus panel weighed the evidence and prepared their consensus statement.
*All medications have both common (generic) and brand names. The brand name is what a specific manufacturer calls the product (e.g., Tylenol®). The common name is the medical name for the medication (e.g., acetaminophen). A medication may have many brand names, but only one common name. This article lists medications by their common names. For information on a given medication, check our Drug Information database. For more information on brand names, speak with your doctor or pharmacist.

Alprostadil self-injection. With this method, you use a fine needle to inject alprostadil (Caverject Impulse, Edex) into the base or side of your penis. In some cases, medications generally used for other conditions are used for penile injections on their own or in combination. Examples include papaverine, alprostadil and phentolamine. Often these combination medications are known as bimix (if two medications are included) or trimix (if three are included).
The common PDE5 inhibitor drugs approved in the United States are sildenafil (Viagra), vardenafil (Levitra and Staxyn, the generic form), tadalafil (Cialis), or avanafil (Stendra). All of the currently approved PDE5 inhibitors work in the same way. They differ in the number of available doses, how quickly they work and last in your system, the dosing, and to some extent in the side effects. However, they generally share the same indications and contraindications. Currently, tadalafil is the only medication that patients can take on a daily basis and is approved for the treatment of both ED and BPH (benign enlargement of the prostate).
Physicians make a diagnosis of erectile dysfunction in men who complain of troubles having a hard enough erection or a hard erection that does not last long enough. It is important as you talk with your doctor that you be candid in terms of when your troubles started, how bothersome your erectile dysfunction is, how severe it is, and discuss all your medical conditions along with all prescribed and nonprescribed medications that you are taking. Your doctor will ask several questions to determine if your symptoms are suggestive of erectile dysfunction and to assess its severity and possible causes. Your doctor will try to get information to answer the following questions:
Alprostadil may also be administered into the urethral opening of the penis. In MUSE (medical urethral system for erection), the man inserts a thin tube the width of a vermicelli noodle into his urethral opening and presses down on a plunger to deliver a tiny pellet containing alprostadil into his penis. The drug takes about 10 minutes to work and the erection lasts about an hour. The main side effect is a sensation of pain and burning in the urethra, which can last about five to 15 minutes.
Fact is, almost all men experience erection problems from time to time. Sometimes it's a temporary condition that will go away with just power of mind or little treatment. But unfortunately in many cases it may be an ongoing problem. Whatever it is, if you don't want to eventually destroy your self esteem and harm relationship with your lover, immediate treatment is required.
Aging, liver and kidney problems, and concurrent use of certain medications (such as erythromycin [an antibiotic] and protease inhibitors for HIV) slows the metabolism (breakdown) of sildenafil. Slowed breakdown allows sildenafil to accumulate in the body and potentially may increase the risk of side effects. Therefore, in men over 65 years of age, in men with significant kidney and liver disease, and in men who also are taking medications called protease inhibitors, the doctor will initiate sildenafil at a lower dose (25 mg) to avoid accumulation of sildenafil in the body. A protease inhibitor ritonavir (Norvir) is especially potent in increasing the accumulation of sildenafil, thus men who are taking Norvir should not take sildenafil doses higher than 25 mg and at a frequency of no greater than once in 48 hours. Other medications that may affect the level of sildenafil include erythromycin and ketoconazole.
A study published in May 2014 in The Journal of Sexual Medicine found that some men can reverse erectile dysfunction with healthy lifestyle changes, such as exercise, weight loss, a varied diet, and good sleep. The Australian researchers also showed that even if erectile dysfunction medication is required, it's likely to be more effective if you implement these healthy lifestyle changes.
While impotence may be the presenting symptom of vascular disease, in neurologic disease impotence generally occurs in the setting of an obvious nervous system disorder, typically in patients known to have spinal cord pathology or neuropathy. Impotent patients should be questioned about decreased genital sensation, which would suggest diabetic, alcoholic, or other forms of neuropathy; weakness, which may accompany multiple sclerosis or spinal cord tumors; and back pain, bowel, and bladder symptoms, which raise concern for cauda equina syndrome. A careful drug history is important in the evaluation of impotence. Drugs that cause impotence (Table 187.3) generally do so by interfering with neurotransmission.
Diabetes is one of the most common causes of ED. Chronically high blood sugar levels can result in nerve damage that affects your body’s ability to translate pleasurable sexual stimulation into an erection. Diabetes can also lead to issues with circulation, which reduces blood flow to the penis and makes it more difficult to keep an erection that is hard enough for intercourse.
Inside the cell, NOS catalyzes the oxidation of L-arginine to NO and L-citrulline. Endogenous blockers of this pathway have been identified. The gaseous NO that is produced acts as a neurotransmitter or paracrine messenger. Its biologic half-life is only 5 seconds. NO may act within the cell or diffuse and interact with nearby target cells. In the corpora cavernosa, NO activates guanylate cyclase, which in turn increases cyclic guanosine monophosphate (cGMP). Relaxation of vascular smooth muscles by cGMP leads to vasodilation and increased blood flow.

It is common for a healthy older man to still want sex and be able to have sex within appropriate limitations. Understanding what is normal in older age is important to avoid frustration and concern. Older men and their partners often value being able to continue sexual activity and there is no age where the man is ‘too old’ to think about getting help with his erection or other sexual problems.

Penile implants: This treatment involves permanent implantation of flexible rods or similar devices into the penis. Simple versions have the disadvantage of giving the user a permanent erection. The latest (and most expensive) device consists of inflatable rods activated by a tiny pump and switch in the scrotum. Squeezing the scrotum stiffens the penis, whether the person is aroused or not. The penis itself remains flaccid, however, so the diameter and length are usually less than a natural erection, and hardness is lacking, although it's sufficient for intercourse.
Stress is another factor that can be a cause or effect of ED. If you're stressed at work, at home, and in your relationships, it's going to take a toll on your sexual function. Your mind is elsewhere, and relaxing when you finally make it between the sheets is a long shot. Now you’re stressed because you can’t get it up (talk about the ultimate catch-22), so you're stuck in this sad, frustrating cycle. “ED really affects the psyche of a guy, regardless of the etiology, Gittens says. “If you have a problem getting an erection one night, you’re probably going to be anxious and worried your partner might see you as less of a man the next time you try to get an erection.” There's a pill that will help with this, and it's not promoted on television with middle-aged men in sports cars. It's a damn chill pill.
Think of erectile dysfunction as your body’s “check engine light.” The blood vessels in the penis are smaller than other parts of the body, so underlying conditions like blocked arteries, heart disease, or high blood pressure usually show up as ED before something more serious like a heart attack or stroke. ED is your body’s way of saying, “Something is wrong.” And the list of things that cause erectile dysfunction can include:
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